The NTSB urged Metro-North to provide an additional level of protection to track workers who depend on train dispatchers for signal protection. The railroad promised to implement the improvements as quickly as possible.

Meanwhile, U.S. Sen. Richard Blumenthal, D-Conn., announced that a Senate committee hearing Wednesday on rail safety will focus on the West Haven death and the May 17 derailment and crash of two Metro-North trains near Bridgeport.

Blumenthal, who will chair the Senate Commerce Committee hearing, said the Bridgeport crash "has rightly focused attention on the safety of our rail systems and how we plan for long-term investments and upgrades in our rail infrastructure. This hearing is an opportunity to hear from a diverse group of stakeholders and to begin to develop a consensus on a coordinated, consistent plan for future investments and improvements."

In an interview, Blumenthal said, "We need to make sure that train transport is safety reliable and that infrastructure gets the kind of investment that's needed.'' He also said the committee would consider whether the worker protection urged by the NTSB in the West Haven case should be legally mandated.

Witnesses at the hearing include Deborah Hersman, chair of the NTSB, who is expected to refer to her agency's preliminary finding that a track flaw is the prime suspect in the board's search for the cause of the derailment of an eastbound Metro-North train, which was then hit by the westbound Metro-North train near the Interstate 95 overpass in Bridgeport. The derailment-crash resulted in the hospitalization of 73 passengers, two engineers and a conductor. Metro-North has estimated there were 250 passengers on each train at the time of the accident.

The NTSB has indicated it won't issue a final "probable cause" finding until next year.

In its investigation of the Bridgeport accident, the board has collected photos, video, data, reports and records, and other evidence; completed mechanical inspections of the rail cars, the track and signal system; interviewed several Metro-North employees, witnesses and first responders; and documented the accident site.

NTSB investigators said rail inspection reports showed that maintenance work had been done in the area of the derailment of the eastbound train in April. The records revealed that a joint bar, used to join two sections of rail together, was cracked and that it was repaired by Metro-North personnel. After the derailment and crash, sections of rail were removed and shipped to the NTSB materials laboratory in Washington for further examination.

The NTSB team said onboard recorders showed that the eastbound train derailed, came to a stop, and was struck about 20 seconds later by the westbound train and that the westbound train engineer applied the emergency brakes before crashing into the derailed eastbound train.

During an NTSB interview, the eastbound train engineer said he saw what he described as an unusual condition on the track as he approached the Interstate 95 overpass. Both trains were reported traveling close to the 70 mph speed limit on that stretch.

Howard Permut, president of Metro-North, told Connecticut lawmakers that the commuter line will ramp up track inspections.

"Operating a safe railroad is the first priority of all the employees at Metro-North Railroad," Permut wrote in a letter.

The Friday evening, rush-hour crash snarled travel in the Northeast corridor and led to a five-day suspension of Amtrak service between New York and Boston.

Other witnesses at Wednesday's Senate hearing will include Connecticut Transportation Commissioner James Redeker; Joseph Szabo, administrator of the Federal Railroad Administration; railroad executives, and a union official.

In the West Haven fatality, the foreman, Robert Luden, 52, of East Haven, was struck and killed by a Metro-North passenger train traveling 70 mph. Luden had requested the section of track be taken out of service for maintenance. Two Metro-North rail traffic controllers, one of whom was a student controller, placed the section out of service. But the student controller reopened the track a little more than an hour later without the approval of the qualified controller or the foreman, the NTSB reported.

On May 4, another Metro-North rail traffic controller mistakenly placed out-of-service track back in service. Two days later, Metro-North instituted additional operations control procedures, but these procedures did not prevent the May 28 fatality.

"The procedures currently in place are ineffective," said the NTSB's Hersman. "Metro-North can take immediate action to ensure the safety of work crews on their tracks. Shunting tracks is simple, feasible and readily available."

The NTSB said Metro-North should require redundant signal protection, such as shunting, for maintenance-of-way work crews who depend on the train dispatcher to control access to occupied sections of track. A shunt is a device that crews can attach to the rails in a work zone that alerts the controller and gives approaching trains a stop signal.

Metro-North said the railroad already has begun work on "a technological solution" beyond the current system of verbal notifications.

Blumenthal said that while he was glad Metro-North was working to add safeguards, "this technology should have been installed before the tragic death of a worker." He added that the shunts are "simple, feasible, inexpensive and potentially lifesaving."